Cancer genetics fundamentals

[The role of matrix metalloproteinases and tissue inhibitors of metalloproteinases in invasion of tumours of neuroepithelial tissue]

Tumour invasion requires degradation of extracellular matrix components and migration of cells through degraded structures into surrounding tissues. Matrix metalloproteinases (MMP) constitute a family of zinc and calcium-dependent endopeptidases that play a key role in the breakdown of extracellular matrix, and in processing of cytokines, growth factors, chemokines and cell surface receptors. Their activity is regulated at the levels of transcription, activation and inhibition by tissue inhibitors of metalloproteinases (TIMP). Changes in expression of MMP and TIMP are implicated in tumour invasion, because they may contribute to both migration of tumour cells and angiogenesis. Alterations of MMP expression observed in brain tumours arouse interest in the development and evaluation of synthetic matrix metalloproteinase inhibitors as antitumour agents.

Synthesis and Biological Evaluation of Heteroaryldiamides and Heteroaryldiamines as Cytotoxic Agents, Apoptosis Inducers and Caspase-3 Activators

The work described here involved the synthesis and biological evaluation of new heteroaryldiamides and heteroaryldiamines. A new general model in which the structures can be adjusted has been applied in this study. Three different structural units can be distinguished: a central nucleus and two symmetric terminal units. The central element is either an aliphatic chain of varying length and flexibility, piperazine, or a polyamine nucleus. However, the terminal units are pyridine, quinoline, indole, benzene or pyrido[2,3-d]pyrimidine with different substituents. The antitumoural activities of the compounds were evaluated in vitro by examining their cytotoxic effects against human breast, colon, and bladder cancer cell lines. Compounds that showed cytotoxic activity were subjected to both apoptosis and caspase-3 assays. With regard to selectivity, the cytotoxicity was also determined in cell cultures of two nontumoural lines. The most promising compounds are 4c, 5c and 7, which are amino-pyridinium, quinolyl-N-oxide, and pyridyl derivatives, respectively, and these reveal a significant in vitro cytotoxicity in at least two of the three cell lines tested. These compounds induced apoptosis and also produced a rapid dose-dependent increase in the caspase-3 level in HT-29 cells. Other encouraging profiles were found, such as those presented by 1k and 8d, which are cytotoxic and apoptotic but do not provoke an increase in the level of caspase-3, or those presented by 2f, 3c and 4a, which are slightly cytotoxic but do not show any other significant activity. The different types of behaviour of each compound are not necessarily parallel in the three cell lines tested.

Genetics and oncology nursing

OBJECTIVES

To review oncology nursing practice in the genetic era, how genetic information is used across the cancer care continuum, practice guidelines, and opportunities for genetic nursing education.

DATA SOURCES

Published articles.

CONCLUSION

Genetic information in oncology health care is used not only to predict risk but to elucidate disease biology, explain individual variation in vulnerability to environmental carcinogens, diagnose and characterize malignancies, design treatment regimens specific to a cancer's genetic fingerprint, develop new, therapeutic modalities, and clarify modulators of drug metabolism, efficacy, and interactions.

IMPLICATIONS FOR NURSING PRACTICE

With current and emerging genetic discoveries, all oncology nurses will use genetic information in their practice.

A Novel Bis-aziridinylnaphthoquinone with Anti-Solid Tumor Activity in which Induced Apoptosis is Associated with Altered Expression Of Bcl-2 Protein

Aziridine-containing compounds have been of interest as anticancer agents since the late 1970s. The design, synthesis, and study of aziridinylnaphthoquinone analogues to obtain compounds with enhanced activity/toxicity profiles are an ongoing research effort in our group. A series of bis-aziridinylnaphthoquinone derivatives has been prepared, and the cytotoxic activities of these synthetic bis-aziridinylnaphthoquinone derivatives has been investigated. The synthetic derivatives displayed significant cytotoxicity against human carcinoma cell lines and weak cytotoxic activities against skin fibroblasts (SF). The bis-aziridinylnaphthoquinone 1 c was the most effective of the tested analogues at reducing the viability of Hep2 cells, with an LD(50) value of 5.23 microM, and also exhibited weak cytotoxic activity against SF cells, with an LD(50) value of 54.12 microM. The DNA alkylation and DNA interstrand cross-linking abilities of 1 c were also investigated. Bis-aziridinylnaphthoquinone 1 c was an effective agent for alkylation of DNA after chemical reduction in vitro, and its bifunctional alkylating moieties were able to cross-link DNA. We also report here our efforts to determine direct antitumor effects of 1 c on Hep2 cells. Growth arrest in Hep2 cells was preceded by early induction of G(2)-M cell cycle arrest at 0.75 microM of 1 c after culture for 24 h, and was then followed by apoptosis after 60 h. This was associated with decreased expression of antiapoptotic bcl2 protein (by 78 %) upon culture with 3.0 microM of 1 c after 60 h. Our results suggest that 1 c is a novel antitumor aziridinylnaphthoquinone with therapeutic potential against solid tumors.

The role of the nurse in cancer genetics

Knowledge gained from the Human Genome Project and related genetic research is already impacting clinical oncology nursing practice. Because cancer is now understood to be a genetic disease, changes in the traditional approaches to prevention, diagnosis, and therapeutic management of cancer are becoming increasingly genetically based. Therefore, to ensure competency in oncology nursing practice at all levels, nurses must incorporate an understanding of the underlying biology of carcinogenesis and the molecular rationale underlying strategies to prevent, diagnose, and treat cancer.